RPH mapping and defaulting behavior

ABSTRACT

An exemplary management method includes receiving at a first network a notice of an intended communication to a called party network, the notice including a first priority indicator, the intended communication requiring a resource for supporting a streaming data protocol in each network between a calling party network and the called party network; forwarding the notice to a second network and toward the called party network, the notice including the first priority indicator; in parallel with said forwarding, mapping the first priority indicator to a second priority indicator and initiating for the intended communication a determination of resource availability for the first network based on the second priority indicator; determining the determination of resource availability for the first network based on the second priority indicator, wherein the determination is for a first resource for the first network; and verifying resource availability for the intended communication.

RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application,“Method And Apparatus For End-To-End Capacity And Priority ManagementThrough Multiple Packet Network Segments”, 61/188,364 filed Aug. 8,200concurrently herewith. The entire teachings of the above applicationare incorporated herein by reference.

FIELD OF THE INVENTION

The invention relates to the field of communication systems, and, morespecifically, to a resource control and policy-based managementmechanisms adapted to implement services including priority services.

BACKGROUND INFORMATION

Often, a call may go through several service provider networks in orderto connect from a calling party to a called party. Each serviceprovider's network may include several domains (or administrativeboundaries). In Time Division Multiplexed (TDM) Networks, resourceclearance using signaling messages is supported through serial resourceclearance on a link-by-link basis. In the serial (or sequential) case,no node transmits a message until first obtaining resource clearancewithin its domain. Accordingly, the total time required to set up a callor session with a link-by-link signaling method is O(Σt_(i)) where t_(i)represents the time it takes for resource clearance in the i-th link.

Priority services is the name given to preferred treatment of certainkinds of traffic (e.g., media/data and signaling) over other kinds oftraffic in, for example, the context of civilian or defensecommunication networks. Priority in a public switched telephone network(PSTN) is performed on a switch by switch basis. Calls for priorityusers, such as government entities pass through switches whilenon-priority traffic is blocked.

Three kinds of priority services exist as present; namely, wirelesspriority service (WPS), Government emergency telecommunications services(GETS) by national communications systems (NCS) and multi-levelprecedents preemption (MLPP) by the United States Department of Defense.

GETS provides an ability to preempt calls at a lower priority than MLPP.GETS also provides for buffer-type queuing of a call such that the callwill be the first call to pass when a necessary resource becomesavailable. Call control functionality includes the decision of choosingwhich call to allow and which call to preempt. Resource control andpolicy-based management functionality includes the decision of when topreempt a call or when to buffer-type queue a call.

Within the context of voice, video and other data communications (e.g.,multimedia communications and the like) via packet based networks (e.g.,Ethernet, etc.) resource clearance is handled on a sequential basis.Methods for preemption and priority handling of voice calls andmultimedia services are also lacking in packet based networks.

SUMMARY OF THE INVENTION

A network element, apparatus and method for combining call admissioncontrol and priority services within different type of networks isprovided. A logical functional entity denoted as a Priority ServicesFunctional Element (PSFE) enables administration of priority servicesand call or session admission control policies through interactions withCall Session Control Function Element (CSCF) and Resource Access ControlFacilities (RACF). Method steps in exemplary embodiments may includeverifying the priority levels, receiving resource availabilityinformation, storing call admission and resource allocation information,identifying path and link information required for an originatedsession, checking available resources at links against requiredresources for the call or session establishment, and communicatingresource availability indication/s (or lack thereof) based on admissioncontrol policies after resource verification.

The PSFE allows for capacity and priority management in parallel overall the links in the bearer path within a particular network. PSFEs indifferent networks can also communicate to enable PSFEs in each networkin the path to perform resource clearance independently and in parallel(i.e., undertaking apparent or actual performance of more than oneoperation at a same time). Proposed methods allow both kinds ofparallelization in networks of different architectures, such as IMS andSIP, and also across varied networks. The PSFE introduces obtainingparallel resource clearance across network boundaries, includingheterogeneous networks. In this manner, calls or sessions may beestablished efficiently, and varied features provided in a multi-medianetwork.

PSFE may use Session Initiation Protocol (SIP) messages to communicatewith Signaling and Service Layer entities, such as Proxy (P-) orInterrogating (I-) CSCFs, Subscriber Information Databases (e.g., HomeSubscriber Server or HSS), and Application Servers (AS). PSFE may alsocommunicate with Transport Layer entities (such as, RACF in an all IMPMultimedia Subsystems (IMS) architecture) using, for example, Diametermessages. However, PSFE may integrate both IMS and non-IMS NextGeneration Service Provider (NGSP) networks and enable efficientresource verification and allocation in the non-IMS NGSP also. Further,the PSFE may also determine resource availability using open loopcontrol or other accounting methods in a network without a RACF.

Next generation networks are not only expected to provide variousmulti-media features as different media are packetized and transportedover the same IP network infrastructure, but also to providewide-ranging interconnectivity among different networks. In many cases,an end-to-end call/session may traverse multiple networks based on thelocations of the end-users. Parallel resource clearance provided by aPSFE is useful in establishing various multi-media services in allIP-based networks regardless of the types of users and may be utilizedin Enterprise, Commercial Service Provider, Civilian Government, andMilitary network segments of IP networks.

Further, the provided PSFE enables use of the priority assignment froman originating network or end-user globally in a trusted manner withprivate mapping of such priority assignments at each separate networkfor specific internal usage within each network. The priority assignmentassociated with a call/session is communicated across multiple networksso that the priority of the session is intact end-to-end. At eachprovider network, the priority assignment is mapped for internal useaccording to pre-defined rules. In this fashion, the PSFE provides atrusted method of communicating and abiding by Resource Priority Headers(RPH) among different service providers (SP).

Although RHP may be provided between two networks currently, SPs may notsupport the RPH values received from other service providers for a hostof reasons. For example, the receiving network simply may not be capableof providing the labeled priority; there may not be a business agreementconcerning such support by the receiving network; the receiving networkmay not trust the priority indicated; and network policies of thereceiving network may require temporary or long-term suspension ofpriority servicing as indicated in the received RPH, which effect isundesirable.

Apparatus and method are provided for capacity and priority managementof a communications network. The provided apparatus and method may beused in a system having a plurality of networks. An exemplary methodincludes receiving at a first network a notice of an intendedcommunication to a called party network, the notice of intendedcommunication including a first priority indicator, with the intendedcommunication requiring a resource for supporting a streaming dataprotocol in each network between a calling party network and the calledparty network. The notice of an intended communication is forwarded to asecond network and toward the called party network. This forwardednotice of intended communication includes the first priority indicator.In parallel with said forwarding, the first priority indicator is mappedto a second priority indicator and a determination of resourceavailability for the first network is initiated based on the secondpriority indicator. Resource availability for the intended communicationthen verified. For example, resource availability of resources necessaryfor the intended communication are not queried and reserved sequentiallyfrom calling to called party but query and reservation of necessaryresources occurs simultaneously or near simultaneously. Further, privatemapping of the priority assignment of the originating network isutilized.

The mapping of the first priority indicator to the second priorityindicator may be based on values negotiated via a key exchange protocol.The key exchange protocol may occur between the between the firstnetwork and the calling party network. The mapping of the first priorityindicator to the second priority indicator may be based on predeterminedand default values. In one embodiment, the first priority indicator isincluded in a resource priority header.

In one embodiment, determining for the intended communication thedetermination of resource availability for the first network based onthe second priority indicator includes reserving for the intendedcommunication the first resource for the first network in the event thefirst resource is available for the intended communication. In anotherembodiment, determining the determination of resource availabilityincludes reserving for the intended communication the first resource forthe first network in the event the first resource is available above athreshold level.

In one embodiment, the notice of intended communication includes apersonal identification number, and an authentication of the intendedcommunication is replayed based on the personal identification number.In a further embodiment, the mapping the first priority indicator to asecond priority indicator maps the first priority indicator to a defaultpriority indicator in the event a value for the personal identificationnumber is unknown. Signaling for the determination of resourceavailability for the first network based on the second priorityindicator may include both the first priority indicator and the secondpriority indicator.

Verifying resource availability for the intended communication mayinclude receiving for the intended communication from a third network asecond indication of resource availability; and the verifying may bebased on the determination of resource availability for the firstnetwork and the second indication of resource availability. A re-invitefor the intended communication may be forwarded in the event verifyingresource availability for the intended communication indicatesavailability of resources from the calling party network to the calledparty network. The third network may be the second network in the eventresource clearance is being fed back to the head end.

In one embodiment, an exemplary method include receiving at a firstnetwork a notice of an intended communication to a called party network,the notice of intended communication including a first priorityaccording to a first priority scheme, wherein the intended communicationrequires at least one resource for supporting a streaming data protocolbetween a calling party network and the called party network; mappingthe first priority to a corresponding second priority for secondpriority scheme utilized in the first network; verifying resourceavailability of at least one resource in the first network based on thecorresponding second priority; and in parallel with said verifying,forwarding the notice of an intended communication to a second networkand toward the called party network prior to receiving an firstindication of resource availability of the at least one resource in thefirst network required for the intended communication.

The mapping of the first priority to the corresponding second prioritymay based on a negotiation via a key exchange protocol between the firstnetwork and the calling party network. The mapping of the first priorityto the corresponding second priority may be based on predeterminedcorrespondences and on default correspondences. In one embodiment, thenotice of intended communication includes a resource priority header.

One embodiment of the method includes receiving at the first network asecond indication of resource availability of at least one resource at athird network required for the intended communication. The third networkmay be the second network when resource clearance is fed back to thehead end. In another embodiment, a re-invite of the intendedcommunication is forwarded to the second network and toward the calledparty network in the event the first indication and the secondindication indicate resource availability for at least one resource ineach network from the calling party network to the called party network.

In context of priority services, such a PSFE can provide higher priorityto priority service users and queue such users' requests for resourceavailability ahead of resource needs from other, routine users. Prioritysession requests and associated priority levels can be identified by thePSFE, for example, through Resource Priority Headers (RPH) in the SIPmessage. It is important to note that to queue priority sessions aheadof routine sessions, no routine session can be allowed in any of thelinks in the priority session path. Coordination of such activitiesacross multiple network segments, which is quite complex among CSCFs,Back to Back user Agents (B2BUAs), and Session Border Controllers (SBCs)in separate network segments, can be achieved via communicating PSFEsdeployed in these segments.

BRIEF DESCRIPTION OF THE DRAWINGS

The teachings of the present invention can be readily understood byconsidering the following detailed description in conjunction with theaccompanying drawings, in which:

FIG. 1 depicts a network topology for facilitating calls through variousnetworks according to an embodiment of the invention;

FIG. 2 depicts an overview of a network topology for facilitating callsthrough an exemplary network according to an embodiment of theinvention; and

FIGS. 3 a and 3 b depict a flow diagram of an exemplary routineaccording to embodiments in accord with the invention.

To facilitate understanding, identical reference numerals have beenuser, where possible, to designate identical elements that are common tothe figures.

DETAILED DESCRIPTION

The subject invention will be primarily described within the context ofvoice calls. However, since the subject invention is directed to thebroader issues of multimedia services (including voice calls) referencesto calls and communications within this specification should be broadlyconstrued to include voice, video, audio, email and other multimediacommunications.

Specific structural and functional details disclosed herein are merelyrepresentative for purposes of describing example embodiments. Exampleembodiments may, however, be embodied in many alternate forms and shouldnot be construed as limited to only the embodiments set forth herein.

The subject invention enables the establishment and management of VoIPtraffic, including traffic of different priority levels, in a network(for example an Internet Protocol (IP) network) with parallel resourceclearance and monitoring of criteria indicative of importance of a newvoice call entering the network, network capability and instantaneousload. Accordingly, an exemplary telecommunications system is describedas one potential environment in which a subject invention operates andexists.

Generally speaking, the invention assists in enabling the followingsystem and network characteristics: (1) A profitable uniformarchitecture that addresses the requirements for both DoD and NCS; (2) Aminimization in the overlap functionality in terms of development andmaintenance of priority service features; (3) A minimization of theimpact on existing architectures; (4) Addressing the requirements of IMSas well as non-IMS environments; (5) An ability to add on priorityservice at any time by a network provider; (6) An interoperability withnetwork solutions of multiple vendors; (7) An ability to pass prioritycalls earlier than routine calls, when a congestion has been cleared andability to maintain “current gets/wps voice functionality” which mayrequire an ability to mimic priority signal queuing from a TDMenvironments; (8) An adaptation to IMS and non-IMS based Next Generationnetworks; (9) An ability to extend and support, at leastarchitecturally, multimedia applications and mid-call features forpriority services in the future; and (10) the providing of calladmission control.

The present invention provides for a logical functional entity denotedas a priority services functional element (PSFE) that integrates withboth IMS and non-IMS networks and environments. Within the context ofnetwork architectures adapted to utilize a PSFE, the PSFE is added tothe architecture as an additional logical entity, such that the rest ofthe network architecture remains substantially unmodified. The PSFEinteracts with the session initiation protocol (SIP) proxies, callsession control functions (PCSCF), resource access control facilities(RACF), (NGSP) and other PSFE entities.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, these elements should notbe limited by these term since such terms are only used to distinguishone element from another. For example, a first element could be termed asecond element, and, similarly, a second element could be termed a firstelement, without departing from the scope of example embodiments. Asused herein, the term “and” is utilized in the conjunctive anddisjunctive senses and includes any and all combinations of one or moreof the associated listed items, and the singular forms “a”, “an” and“the” are intended to include the plural forms as well, unless thecontext clearly indicates otherwise. Unless otherwise defined, all terms(including technical and scientific terms) used herein have the samemeaning as commonly understood by one of ordinary skill in the art towhich example embodiments belongs. It will be further understood thatterms, such as those defined in commonly used dictionaries, should beinterpreted as having a meaning that is consistent with their meaning inthe context of the relevant art and should not be interpreted in anidealized or overly formal sense unless expressly so defined herein.

It is noted that the PSFE can also perform its intended function withoutthe use of a RACF. In that instance, control of specific links isachieved via accounting based methods (whereas control of an entirenetwork is performed with a RACF). In one embodiment, a standard orcommercial network architecture is modified to use a PSFE by providersseeking NCS compliance, though mandatory use of PSFE is envisioned forDoD networks. Optionally, PSFE interaction with H323 systems isprovided. The invention may be utilized within the context of SIP, H323,voice over IP (VoIP) or, more generally, X over IP network (XoIP), whereX is a voice, video or multimedia communication.

The PSFE may provide priority signal message queuing (queuing tracked bylinks of a transport path) and preemption capabilities (i.e., it is ableto identify the calls that need to be preempted to decongest certainlinks). Queuing in this context refers to the buffering-type queuing asis known in the prior art. Queuing in the inventive context is termed bythe inventor as protocol level queuing and includes buffering-typequeuing as well as call state queuing. Queuing a call or other serviceoccurs when, for example, resource availability is verified for a linkduring parallel resource clearance. In this case the call is notdropped; rather, its state is stored by the PSFE until appropriateresources become available for the call in each network to be traversedby the call. Being held or stored means that the state information ofthe call is stored for subsequent use. The state of a call comprises thecall source, the call destination, the resources needed to support thecall, and so on.

Call admission control in a simple form is defined as determining whichcalls should be dropped and which calls should be allowed. Priorityservices in a simple form is defined as providing preferential treatmentto some calls and not other calls. To effectively perform call admissioncontrol and priority services, the network needs to have knowledge ofthe calls in the system, their actual call paths (control plane andmedia plane paths) as well as the transport resources available in thenetwork. One embodiment of the invention includes within one entity (thePSFE), priority and call information (e.g., number of calls in system,available transport resources and the like) needed to combine andcontrol call admission and priority service functions. Thus, the PSFEhelps to simplify network control plane architecture by combiningmultiple priority-related functions (e.g., call admission control andpriority services) in a single functional entity.

The PSFE optionally communicates via Diameter to a RACF. The PSFE mayalso be call-state aware such that it can identify calls over links in atransport network (transport resource aware). In some embodiments, thePSFE continuously polls a RACF to identify availability of resource suchthat resource clearance of multiple call paths may be handledefficiently. In some embodiments the PSFE operates without a RACF (E.g.,for open loop or accounting based controls).

In some embodiments, additional support for the PSFE is beneficial.Specifically, at times it may be appropriate for a RACF to pass linkinformation of a media path (e.g., via a PDFE) to the PSFE. However,this will be needed only under certain cases. RACF link information isnot needed when a call flows or when a priority call is cleared. For apriority call not cleared by the RACF, link information is needed forall subsequent RACF-cleared calls so that the availability of resourcessupporting the non-cleared priority calls can be determined.

Optionally, a P-CSCF (or a Proxy in non-IMS cases) will pass every SIPmessage it receives to the PSFE. Optionally, a new 5xxx message toconvey network attempts (e.g., in the case of priority call queuing) isappropriate. Optionally, a protocol between the PSFE and NGSPs may beadapted to address fault tolerance issues such that fault tolerancefunctionality need not be distributed across a number of CSCFs.

FIG. 1 depicts a network topology facilitating calls through variousnetworks according to an embodiment of the invention. Specifically, FIG.1 depicts an exemplary communications system 100 according to anembodiment of the invention. In addition to architecture, FIG. 1 alsodepicts control and bearer signal paths, which signal paths areassociated with reference numerals indicative of a temporal order ofutilization in establishing and tearing down calls. FIG. 1 will bediscussed in conjunction with other FIGs. to illustrate various callflow examples according to embodiments of the present invention.

Specifically, FIG. 1 depicts a plurality of networks including a callingparty home network 110, a called party home network 120, a calling partyvisited network 130 and a called party visited network 140.

The calling party home network 110 comprises one or more applicationservers (AS) modules 112, a home subscriber server (HSS) 114 and aserving call session control function (S-CSCF) 116.

The called party home network 120 comprises one or more applicationservers (AS) 212, a home subscriber server (HSS) 214, a serving callsession control function (S-CSCF) 116 and interrogating call sessioncontrol function (I-CSCF) 128.

The calling party visited network 130 comprises a P-CSCF 131, a priorityservices functional element (PSFE) 132, a resource allocation controlfunction (RACF) 133, a backbone packet network 136 and an access network137. The RACF 133 includes a policy decision functional element (PD-FE)134 and a traffic resource control functional element (TRC-FE) 135.

The called party visited network 140 comprises a P-CSCF 141, a priorityservices functional element (PSFE) 142, a resource allocation controlfunction (RACF) 143, a backbone packet network 146 and an access network147. The RACF 143 includes a policy decision functional element (PD-FE)144 and a traffic resource control functional element (TRC-FE) 145.

The network 100 FIG. 1 may be modified to represent a conventionalnetwork by removing each PSFE and RACF from the calling and called partyvisited networks. In this case, a call between A and B is initiated inaccordance with the numbered signal paths 1-16; namely (1) a callinvitation is communicated from Endpoint A via access network 137 tobackbone packet networks 136, then (2) to P-CSCF 131 and then to (3)S-CSCF, which (4) queries HSS 114, (5) AS 112 and (6) DNS 150 toretrieve the appropriate information pertaining to the called party andits home network. S-CSCF 116 then (7) communicates with the I-CSCF 128of the called party home network. I-CSCF 128 propagates the request (8)to S-CSCF 126, which communicates (9) with its local HSS 124 and (10) AS122 together necessary information regarding Endpoint B. S-CSCF then(11) propagates a message to the P-CSCF 141 of the called party visitednetwork 140 associated with Endpoint B.

The above steps (1-11) are fairly conventional. In a conventionalnetwork, the P-CSCF 141 communities with a backbone packet network 146to identify those router and other output ports within the RTP streamcapable of supporting the call. This information is propagated back tothe P-CSCF 131. The P-CSCF 131 and P-CSCF 141 cause their respectivebackbone packet networks 136 and 137 provide a communication pathsupporting the call within the RTP stream.

The network 100 of FIG. 1 is depicted as including a PSFE and RACFwithin each of the calling and called party visited networks. Theinteraction of these components with each other and existinginfrastructure will be described in more detail below with respect tothe remaining figures.

Within the context of the present invention, a SIP Proxy (or P-CSCF)continues to work as a transaction-stateful or call-stateless proxy asregards all other features. All calls, independent of priority, to orfrom a SIP Proxy (or P-CSCF) are locally looped to a PSFE. The PSFEoptionally maintains call-state information (including linkidentification information for the traversed links associated with thecall) for all calls. Communications between PSFE and RACF are viadiameter for necessary resource clearance, and various demands andrequests necessary transport path information.

Advantageously, the PSFE enables parallel resource clearance acrossnetwork boundaries, queuing a call in itself until resources becomeavailable. In order to set up calls in parallel across multiple links,the following call control functions are provided: i) call-stateawareness about existing and in-progress calls/sessions; ii) ability togather information regarding resource usages at the links and networkelements, and iii) ability to correlate call path within its domain fromthe addresses. In one embodiment, the PSFE obtains all necessaryresource clearance for a particular call in one parallel operation. ThePSFE performs necessary signal message queuing when it decides thatresources are available with its domain for a call as part of resourceverification. The PSFE routinely polls the RACF to identify resourceavailability. The PSFE sends back appropriate (e.g., standard SIP) errormessages to the SIP Proxy (or CSCF) to signal a call that is to beblocked, if need be (e.g., a higher priority call is queued). In theevent of resource availability for the PSFE's own network and receipt ofan indication of resource availability for another network to betraversed by an intended call, the PSFE sends back appropriate(standard) SIP protocol messages to the SIP Proxy (or CSCF) to signal acall that is to be allowed. The PSFE initiates 3rd party calling forqueued calls via the P-CSCF, as and when the resources for those callsbecome available. In the case of a 3^(rd) party call, the networkoperates to communicate (i.e., call back) both the calling party and thecalled party at a later time.

While denoted as a realtime transport protocol (RTP) stream in FIG. 1,the backbone packet networks may communicate via any streaming protocol,such as transmission control protocol (TCP), user datagram protocol(UDP) and the like. Signaling messages are sent from the call controlelements in the originating network up to the call control elements inthe terminating network for setting up end-to-end voice, data and videosessions across multiple networks. Different mechanisms for carryingsuch messages can be put in place depending on the network topology,interconnectivity, and protocols supported by the underlying network.

FIG. 2 depicts an overview of a network topology for facilitating callsthrough an exemplary network according to an embodiment of theinvention. A method according to the invention proposes to obtainresource clearance in parallel across all links within a networkboundary, as well as obtain resource clearance across several networkboundaries. A conventional system employs sequential resource clearance,in which no node transmits a message until that node first obtainsresource clearance within its domain. (i.e., serial resource clearanceis accomplished on a link-by-link basis). In contrast, in parallelresource clearance as provided by the PSFE, the apparent or actualperformance of more than one resource clearance operation occurs at atime, by the same or different devices and modules. In the parallelcase, the various time requirements for resource clearance (Ti) aretriggered as and when a resource availability request is received indomain i, and the domain i does not wait for the completion of Ti beforesending a resource availability request to domain i+1. In this manner,multiple domains may be obtaining resource clearance without having towait for the completion of resource clearance in a previous one/s. Whenthere are multiple links in each domain, resources clearance within adomain may also be performed in parallel. For example, by using PSFEsfor obtaining resource clearance in parallel across all links within anetwork boundary, as well as obtaining resource clearance across severalnetwork boundaries, the time required for resource clearance will bereduced to O(Max(t_(i))), where Max(t_(i)) represents the maximum of allt_(i), i.e., the maximum of all individual resource clearance times inindividual links. Accordingly, the time required to process and transmita message in a PSFE enabled network is much lower than the time requiredto wait for clearance on all links in a conventional network.

Such a methodology leads to one or more benefits. For example, settingup calls and sessions across an IP network will be more efficient andfaster, which will reduce post-dial delay. Calls and sessions will havehigher probability to complete set-up protocol exchanges before anyparticular timer expires, such as during set up when the networks arecongested. For an end-to-end call which encounters multiple serviceprovider (SP) networks, each SP network may be provided with informationon resource needs and priority for the call/session, and the separatenetworks are able to assess and clear the calls. The time for set up ofa call or a session that crosses several network domain boundaries(resulting from reasons, such as, administrative domains, geographicaldistribution, and population density, etc, even within a same SPnetwork) will require only the maximum time required for setup in any ofthe domains.

A further overview of the mechanism and methodology for parallelresource clearance by the PSFE across multiple networks required for anintended call is described in U.S. patent application Ser. No. ______entitled End-To-End Capacity And Priority Management Through MultiplePacket Network Segments, filed Dec. ______, 2008 which is hereinincorporated by reference. Further, beneficial applications can bedeveloped using the methodology provided. For example, many callscenarios require connection to media servers, at times prior to callestablishment and in other cases in mid-call, and the access path tomedia server may differ from that carrying the bearer packets from thecaller to the called. The proposed methodology enables reservations andresource management across such different paths in parallel. Inaddition, the methodology of the invention facilitates the establishmentof multiple conference legs, where call legs for an intendedcommunication may include legs for each end point (end point referringto users, media server, conferencing server, and the like) and for eachmedia type (e.g., video, audio, text, data, and the like, and somecombination thereof) and some combination thereof. For example, ifcapacity is constrained to support all media types in a multi-mediacall, reservations across media types in parallel can be utilized toenable early establishment of calls with one media requiring lessercapacity when required capacity to support all media types isunavailable at the start of the call. Later, other media types can beadded when additional capacities become available as further describedin U.S. patent application Ser. No. ______ entitled Incremental AdditionAnd Scale-Back of Resources Adapting to Network Resource Availability,filed Dec. ______, 2008 which is herein incorporated by reference.Further conferences with multiple end points across various network maybe initially established with less than all of the multiple end points,with endpoints called back as resource become available as described inU.S. patent application Ser. No. ______ entitled Network Call Back ToAdd Conference Participants And/Or Media, filed Dec. ______, 2008, whichis herein incorporated by reference.

An overview of the mechanism for the parallel resource clearance by PSFEwith Resource Priority Header (RPH) mapping and defaulting acrossmultiple networks is outlined in FIG. 2. For example, a priority callinitiated from a caller in network A to a called end in network C willtraverse network 200, which comprises networks A 210, B 220 and C 230.Alternatively stated, a call initiated from the caller to the called endwill traverse networks N₁, N₂, N₃, N_(i), . . . N_(M), where N₁ is thehead end, and N_(M) is the tail end of the call. The head end refers tonetwork components like proxies, CSCF and PSFEs closest to the caller,while tail end refers to those network components closest to the calleduser. Also note that only three networks, namely A, B and C areillustrated for simplicity.

Each network includes a CSCF (212, 222, 232), a PSFE (212, 224, 234), aRACF (216, 226, 236), and a backbone packet network (218, 228, 238). Thebackbone packet network in each network may include a plurality ofservers (219, 229, 239). The RACF may include a policy decisionfunctional element (PD-FE) and a traffic resource control functionalelement (TRC-FE) (not shown)

All calls, independent of priority, to or from a CSCF are locally loopedto a PSFE. The PSFE maintains call-state information (including linkidentification information for the traversed links associated with thecall) for all calls. Communications between PSFE and RACF are viaDiameter for necessary resource clearance, and various demands andrequests necessary transport path information.

When a call passes through networks A, B and C, then the PSFE element ineach of those network clouds is responsible for obtaining necessaryresource clearances in its own network respectively. In parallel withthe verification of resource availability within its network, the PSFEforwards the notice of an intended communication to the next network andtoward the called party network. The priority of the intendedcommunication may be indicated in a Resource Priority Header (RPH) ofthe notice

As resources become available in each of the networks, the PSFE in thatnetwork awaits for the clearance to arrive from the tail end of thecall. In other words, network B waits for the clearance from network C,and network A waits for the clearance from network B. Thus, network Awill not receive clearance until both networks C and B have necessaryresources for the call. At this point the PSFE in network A,communicates to the CSCF in network A (or the SIP proxy in network A)and triggers a re-invite from the caller to the called user. In analternative embodiment, PSFEs in each of the networks await for theresource clearance indication to arrive from the head end direction ofthe call.

The relation between any two networks (e.g., network A, network B) orservice providers may vary in one of two ways. In a first instance, SPsmay trust the priority indicator received in a notice of intendedcommunication and forward the notice without verification of thepriority therein. For example, as the originating network A sends thesession INVITE through the RPH, the PSFE in receiving network B truststhe priority indicated in the RPH and needs no extra verification. Trustmay be achieved through either implicit business agreements, or througha technological component. The technological component may be associatedwith the PSFE. For example, the PSFE in the receiving network mayexchange keys with PSFEs of known service providers, via a protocol(e.g., the peer interface of the PSFE). In this case, the receivingnetwork B uses the same priority indicated in the RPH received fromnetwork A, within its own network (here, network B). If network B is notthe call terminating network and needs to send the INVITE to follow-onnetworks (network C), the received RPH from network A will be sentwithout any modification.

On the other hand, when there is no trust mechanism established betweenSPs, the receiving network (e.g., network B or C) needs to verify thepriority of the call as indicated in the notice of intendedcommunication. For example, priority calls may be first authenticated bya personal Identification Number (PIN) before the notice of intendedcommunication is signaled for session start. After verification of thePIN at the originating network A, the PSFE in the originating network Ainserts the PIN in a header extension and sends it toward thedestination network. The PSFEs in receiving networks (networks B and C)in the call/session path are able to identify the PIN in the header andreplay the authentication of the call through an authentication server.For security, the PIN number may be sent in an encrypted manner, and notin clear text. After authentication, the PSFEs in networks B and C areable to map and assign an RPH for the session solely for use in theirown networks according to a previously set policy.

Should a PSFE receive a priority call without an accompanied PIN, thepriority in the receiving network (networks B and C) may be assigned adefault value for internal use, which may be set by a predeterminedpolicy.

PSFEs in receiving networks (networks B and C) may stack or add theinternal priority information as additional header extensions (to beused only in their own networks) over the original header, and removethese additional header extensions if the notice of intendedcommunication needs to be sent to other follow-on networks (e.g., fromnetwork B to network C). In effect, if the receiving network sends thenotice of intended communication to follow-on networks, the original RPHis sent as received, without any modification.

In each of these network segments one or multiple PSFE communicates withthe corresponding CSCF and RACFs. For example, if resource clearance ispropagated toward the tail end, on receiving a new session or callrequest through SIP INVITE and from the identification that the call orsession needs to be forwarded to the CSCF in Network B, the PSFE inNetwork segment A forwards a resource assessment request to PSFE inNetwork segment B, while looking into the resource requirement versusavailability in Network segment A. The resource assessment requestcarries a RPH for network A and a PIN. The PSFE in Network segment Aalso follows up with a message to the CSCF and PSFE in network segment Bregarding resource availability in Network segment A after itsdetermination.

The PSFE in Network segment B performs the same function as the PSFE inNetwork segment A, which is sending a resource assessment request toPSFE in Network segment C by recognizing that the call or session needsto be sent to Network segment C while it gets engaged in verifyingresource availability in Network segment B. The PSFE in Network segmentB verifies the PIN received from the PSFE in Network segment B, ifnecessary. The PSFE in Network segment B maintains a map of RPHs betweenNetwork segment A and B, so as to allow internal use of correspondingRPHs for Network segment B whole replying with RHPs for Network segmentA. PSFE in Network segment B also follows up with a message to the CSCFand PSFE in Network segment C regarding resource availability in Networksegment B after its determination. PSFE in Network segment B alsoforwards the resource availability determination that it received fromPSFE in Network segment A.

The CSCF in Network segment C determines that the called end is inNetwork segment C. PSFE in Network segment C determines the resourceavailability for the requested call or session for the Network segment Cusing a mapped RPH and together with messages received from PSFEs inNetwork segments A and B, determines the end-to-end resourceavailability before informing its decision on call or session admissionto the CSCF in Network segment C. CSCF in Network segment C then admitsor disallows the call based on PSFEs' decision (based on resourceavailability information for PSFEs in A, B and C).

In other embodiments, a transit network may be interposed two of theNetwork Segments illustrated (e.g., between Network segments A and B,Network segments B and C). A transit network is used for bulk transportbetween networks providing user services. Such transit networks providebulk transport services only and do not have call or session managersassociated therewith but may honor Service Level Agreements (SLA), whichare primarily based on statistically averaged call or sessionperformance over time. SLAs are generally based on connectivity metricssuch as, downtime, reliability and availability measures, and bytessent/received, and Quality of Service metrics such as, delay, delayvariation, packet loss and packet throughput.

Transit networks do not provide individual call or session control andmanagement. Thus, the transit network and its partners will typicallyhave an overall bulk transport carrying agreement but the transitnetwork does not support specifically any individual call or sessionrelated characteristics. For example, a transit network may be outfittedwith a PSFE, RACF and a Backbone network but not have a CSCF.

For calls passing through such core transport networks or transitnetworks, obviously call or session management is not performed by thecore transport service provider. Thus, the originating and/orterminating network service provider on either side of the transitnetwork is responsible to provide end-to-end call or session admission,and management. Accordingly, the PSFE also is enabled to negotiate anddetermine resource availability from the transport-only networks. Inaddition, as described above, the PSFE performs resource assessment inits own network and forwards a resource assessment and clearance requestthrough SDP offers to PSFEs in the call path as determined from thedestination URI. Based on received the availability information for itsown network and other networks in the call path including any interposedtransit networks, a PSFE decides on call admission and instructs theCall Session Control Function Elements (CSCF) for implementing call orsession admission decisions.

FIGS. 3 a and 3 b depict a flow diagram of an exemplary routineaccording to embodiments in accord with the present invention. The callblocking call flow, call queuing and call creation for the parallelresource clearance of 300 of FIGS. 3 a and 3 b will be described withinthe context of the communications system 200 of FIG. 2. Specifically,control signal paths between calling Endpoint-A 302 in network A (i.e.,calling party network) and called Endpoint-C of network C (i.e., calledparty network) as can be gathered from FIG. 2 comprise, in the ordernamed, CSCF-A 212, PSFE-A 214, CSCF-B 222, PSFE-B 224, CSCF-C 232,PSFE-C 234.

Referring now to FIG. 3 a, at 301 an invite message is propagated fromcalling Endpoint A to CSCF-A 212 , then at 302 to CSCF-B 222, andfinally at 303 to CSCF-C 232. In general, each network sends an invitemessage toward the called network until the called network is reached bythe notice of intended communication. The invite message includes theResource Priority Header (RPH) for Network A (RPH-A). The invite messagemay also include a Personal Identification Number (PIN) associated withthe authentication of the call. The PIN may be encrypted.

In parallel with the propagation of the invite message, each PSFE (214,224, 234) verifies resource availability for a resource required forintended communication in response to a reserve message (311, 312, 313).

Every SIP invite message sent out by N_(i) contains the RPH value sentin the original INVITE from the calling party network. However,internally N_(i) the corresponding PSFE_(i), might use an RPH value thatis understood and utilized by network N_(i) only. Thus, a mappingbetween the RPH values (viz., RPH-A and RPH-i is maintained by P_(i)).Messages going out toward the head end or tail end from Pi will containRPH-A, and messages for internal consumption will contain RPH-i. TheseRPH values are negotiated via a key exchange protocol between variousPSFEi's. If no protocol is exchanged between various Pi's to exchangeRPH information, a default RPH value may be utilized. Thus at 310,PSFE-B verifies the PIN for the call and maps RPH-A of the notice ofintended communication to RPH-B for internal use. At 312, PSFE-Cverifies the PIN for the call and maps RPH-A of the notice of intendedcommunication to RPH-C for internal use

It should be noted that RPH is a specific SIP header extension. Ingeneral, ones of the networks may use standard or proprietary signalingother than SIP. Thus in alternate embodiments, mapping between RPH andproprietary protocol fields indicating priority of the call/session willbe undertaken.

When an invite message enters a first network (e.g., network C), thecorresponding PSFE (e.g., PSFE-C 234) checks the RPH to providetreatment appropriate to its priority level, such as attempting toreserve necessary bandwidth for the call and queues the call in itsstack. If P_(i) has a trusting relationship with P_(A), then P_(i) usesthe RPH-A for priority treatment within N_(i). The key exchange betweenvarious Pi's is not addressed here as any appropriate key exchangemechanism between servers should suffice. If P_(i) does not have atrusting relationship with P_(A), then P_(i) uses the PIN in the INVITEfrom P_(A) and authenticates the call and its priority level through anauthentication server. After authentication, P_(i) sets RPH-i for use inN_(i) solely, mapping RPH-i from RPH-A according to predeterminedpolicy. RPH-A is not discarded from the signaling; rather RPH-i is addedon top. In case P_(i) receives an INVITE without an accompanied PIN,P_(i) sets a default RPH-i value according to the predetermined policyof N_(i). If P_(i) needs to send messages upstream to P_(i+1), ordownstream to P_(i−1), P_(i) removes the RPH-i header extension from themessage leaving the originally received RPH-A intact.

The corresponding PSFE (e.g., PSFE-C 234) determines from correspondingRACF (e.g., RACF-C 236) if resources are available for all the linkswithin the first network (e.g., network C) for this particular call. Inone embodiment, if requested resources are not available, the call isqueued, and no lower or equal priority call is allowed until thisparticular call gets a chance to obtain the requested resource capacity.

For example, in case of dynamic real-time bandwidth management,corresponding RACF (e.g., RACF-C 236) listens to the SNMP messages frommultiple switch/routers in that network in parallel and determines ifall the necessary link/s that constitute the call have enough resource/savailable. In cases where dynamic bandwidth management is not requiredand mere call counting or bandwidth counting will suffice, thecorresponding PSFE or the corresponding RACH may be directly involved inbandwidth or call counting and determine the availability of thenecessary resource/s.

The act of queuing the call and communication with the correspondingRACH ensures that resources are obtained in parallel in first network(e.g., network C). In case of dynamic bandwidth management, allcorresponding routers in the network send updates in parallel to thecorresponding RACH of the first network. The corresponding PSFE thenmakes decisions based on the query to the corresponding RACH of thenetwork as described above.

In another embodiment when a transport network is interposed networks Aand B, the originating network's (A) PSFE learns about the network wherethe call/session needs to be forwarded to (i.e., network B) and theintermediate transport network (A′) from the called URI. The PSFE thenverifies the SLA agreed with the transport network (A′) and determinesif the SLA assures the requirements for the call/session in progress.The originating network's PSFE forwards the call/session request alongwith resource needs to the PSFE in the next network (B) in thecall/session path (via the CSCFs).

A PSFE sends a Held message toward the next PSFE closer the head-endPSFE only when the resources in all subsequent networks are availablefor the intended call. If the PSFE is in the called party network (e.g.,network C), at 321 the held message may be forwarded based on resourceavailability within the called network alone. The held message isforwarded between PSFE via corresponding CSCF at 322, 323. referring toFIG. 3 b, for PSFE in a first network other than called party network(i.e., intermediate networks (e.g., network B) and the calling partynetwork (e.g., network A)), at 324 a Held message is forwarded only ifeach network from first network in question to the called party networkhave resource availability for the intended communication. Again, theheld message is delivered to the head end PSFE via the correspondingCSCF of the first network at 325 and the head end network at 326. Inother words, the held message is forwarded between PSFE viacorresponding CSCF (325 and 326). A Held message is essentially acommand that instructs the CSCF that resources are held for a user, butare not yet consumed. The Held message may be implemented as a 1xxmessage.

As resources become available in each of the networks, the PSFE in thatnetwork await for the clearance to arrive from the tail end of the call.In other words, when a call passes through networks A, B, and C, B waitsfor the clearance from C, and A waits for the clearance from B. Thus Awill not receive clearance until both C and B have necessary resources.All the intermediate networks' PSFEs and the final network PSFE sends a1xx message indicating that resources are held when the resources becomeavailable. Note that, in an embodiment with a transport network A′interposed networks A and B, PSFE in A also has verified that thetransport network A′ can assure the resources required in A′ throughcommunication with the transport network.

In an alternate embodiment, the PSFE sends an indication of resourceclearance to the head-end as soon as resources are determined to beavailable in its own network and the decision about final call admissionmay be based on resources availability across the various PSFE asdetermined by the PSFE at the head end network (i.e., calling partynetwork). In another embodiment call admission may be based on minimumpossible resource is available across the various PSFE.

When PSFE at the calling party network determines that there is ofresource availability for end-to-end communication contemplated, at 327that PSFE forwards a “held message’ that triggers corresponding CSCF toinitiate a SIP Re-Invite from the calling network CSCF to the callednetwork CSCF (328, 329, 330). Alternatively, an SDPReoffer may betriggered.

In respond to the re-invite message, a ringing message is propagatedfrom the called endpoint to the calling endpoint (331, 332, 332). When aPSFE obtains the Re-Invite message, the necessary resource is locked inusing the queued information associated with the call via lock message(335, 336, 337). A Lock message is essentially a command that instructsthe PSFE that resources are now being used. The Lock message may beimplemented as another 1xx message or could be piggybacked with‘ringing’ message. Prior to the PSFE receipt of the Lock message, thecall is merely queued and the resources are not being consumed. Messagesneed not be in SIP, but can be implemented in DIAMETER or any otherprotocol.

The PSFE of the present invention advantageously isolated Parallel CallAdmission and Priority Services development so that such services areeasier to develop and maintain. Moreover, such services may now beprovided without service and software replication with respect to vendorproduct offerings. Parallel Call Admission and Priority Services can bean optional service required by a customer and can fit IMS and non-IMSnetworks, including H323. With the novel PSFE, newer DISA and NGPSfeatures are easier to develop. In this manner, new features like“priority conference call reservation” of priority conferences may beimplemented. In addition, the PSFE relieves the burden of having a CSCFor any other fully operational SIP Proxy maintain resource awareness(i.e., call states with respect to links). The PSFE provides resourcecontrol and policy-based management mechanism adapted to implementpriority services in a packet network environment, such as describedherein.

The above-described embodiments of the invention may be implementedwithin the context of methods, computer readable media and computerprogram processes. Generally speaking, methods according to theinvention may be implemented using computing devices having a processoras well as memory for storing various control programs, other programsand data. The memory may also store an operating system supporting theprograms. The processor cooperates with conventional support circuitrysuch as power supplies, clock circuits, cache memory and the like aswell as circuits that assist in executing the software routines storedin the memory. As such, it is contemplated that some of the stepsdiscussed herein as software processes may be implemented withinhardware, for example as circuitry that cooperates with the processor toperform various steps. Input/output (I/O) circuitry forms an interfacebetween the various functional elements communicating with the device.

A computing device is contemplated as, illustratively, a general purposecomputer that is programmed to perform various control functions inaccordance with the present invention. The invention also can beimplemented in hardware as, for example, an application specificintegrated circuit (ASIC) or field programmable gate array (FPGA). Assuch, the process steps described herein are intended to be broadlyinterpreted as being equivalently performed by software, hardware and acombination thereof in various alternative embodiments.

The invention may also be implemented as a computer program productwherein computer instructions, when processed by a computer, adapt theoperation of the computer such that the methods and/or techniques of thepresent invention are invoked or otherwise provided. Instructions forinvoking the inventive methods may be stored in fixed or removablemedia, transmitted via a data stream in a signal bearing medium such asa broadcast medium, and/or stored within a working memory within acomputing device operating according to the instructions.

While not specifically noted, it will be appreciated by those skilled inthe art that various network management system (NMS) and elementmanagement system (EMS) are used to manage the various functionalelements discussed herein, including the new PSFE. Each PSFE is managedby an appropriate NMS and/or EMS, which is selected according to thenetwork within which the PSFE operates. Thus, the PSFE is operable toprovide bridge and information and protocol bridge between variousmanagement systems such that call state aware and priority state awareinformation may be utilized throughout a large group of networks, asdiscussed above.

Within the context of a NMS or EMS utilizing the present invention, aninstantiation of an application such as an IMS application includes aPSFE that is logically and/or physically disposed between the RACF andCSCF of a network to perform the various functions discussed above. Assuch, one embodiment of the invention comprises a method for adapting acontrol plane of a communication network normally using a call sessioncontrol function (CSCF) in communication with a resource access controlfunction (RACF), where the method includes providing a priority servicefunctional element (PSFE) between each RACF and its corresponding CSCFto verify a priority level for each call, receive resource allocationinformation from the RACF, store a resource allocation for each call,and cause the CSCF to preferentially allocate resources to high prioritycalls as discussed above with respect to the various figures.Instantiations supporting the PSFE may be provided on a single server ormultiple servers, and/or within a single network or multiple networks.

An apparatus according to the invention is adapted for use in a systemcomprising a plurality of networks, each of which include a resourceaccess control function (RACF), a call session control function (CSCF)and a packet network supporting, illustratively, a Realtime TransportProtocol (RTP) stream between the calling and the called party networks.The PSFE advantageously provides a knowledge of call-states as well asthe “links” that they pass through, in order to block routine calls(both NCS and DoD), queue priority calls against the “links” that theywill use (NCS) and tear down/preempt calls, under certain conditions,based on the “links” that they traverse (DoD). The PSFE also provides anability to perform 3^(rd) party calling (network initiated) when queuedcalls are processed, and an ability to obtain “link” (i.e., transportresource paths) information from certain elements in the network. Thisinformation is then passed to the relevant management system.

Reference herein to “one embodiment”, “another embodiment” or “anembodiment” means that a particular feature, structure, orcharacteristic described in connection with the embodiment can beincluded in at least one embodiment of the invention. The appearances ofthe phrase “in one embodiment” in various places in the specificationare not necessarily all referring to the same embodiment, nor areseparate or alternative embodiments necessarily mutually exclusive ofother embodiments. Although various embodiments which incorporate theteachings of the present invention have been shown and described indetail herein, those skilled in the art can readily devise many othervaried embodiments that still incorporate these teachings.

1. A method comprising: receiving at a first network a notice of anintended communication to a called party network, the notice of intendedcommunication including a first priority indicator, wherein the intendedcommunication requires a resource for supporting a streaming dataprotocol in each network between a calling party network and the calledparty network; forwarding the notice of an intended communication to asecond network and toward the called party network, the notice ofintended communication including the first priority indicator; inparallel with said forwarding, mapping the first priority indicator to asecond priority indicator and initiating for the intended communicationa determination of resource availability for the first network based onthe second priority indicator; determining for the intendedcommunication the determination of resource availability for the firstnetwork based on the second priority indicator, wherein thedetermination is for a first resource for the first network; andverifying resource availability for the intended communication.
 2. Themethod of claim 1 wherein the mapping of the first priority indicator tothe second priority indicator is based on values negotiated via a keyexchange protocol.
 3. The method of claim 1 wherein the mapping of thefirst priority indicator to the second priority indicator is based onvalues negotiated via a key exchange protocol between the first networkand the calling party network.
 4. The method of claim 1 wherein themapping of the first priority indicator to the second priority indicatoris based on predetermined values.
 5. The method of claim 1 wherein themapping of the first priority indicator to the second priority indicatoris based on at least one default.
 6. The method of claim 1 wherein thefirst priority indicator is included in a resource priority header. 7.The method of claim 1 wherein determining for the intended communicationthe determination of resource availability for the first network basedon the second priority indicator comprises: reserving for the intendedcommunication the first resource for the first network in the event thefirst resource is available for the intended communication.
 8. Themethod of claim 1 wherein determining for the intended communication thedetermination of resource availability for the first network based onthe second priority indicator comprises: reserving for the intendedcommunication the first resource for the first network in the event thefirst resource is available above a threshold level.
 9. The method ofclaim 1 wherein the notice of intended communication includes a personalidentification number, the method further comprising: replaying anauthentication of the intended communication based on the personalidentification number.
 10. The method of claim 9 wherein the mapping thefirst priority indicator to a second priority indicator maps the firstpriority indicator to a default priority indicator in the event a valuefor the personal identification number is unknown.
 11. The method ofclaim 1 wherein signaling for the determination of resource availabilityfor the first network based on the second priority indicator includesboth the first priority indicator and the second priority indicator. 12.The method of claim 1 wherein verifying resource availability for theintended communication comprises: receiving for the intendedcommunication from a third network a second indication of resourceavailability; and wherein the verifying is based on the determination ofresource availability for the first network and the second indication ofresource availability.
 13. The method of claim 1 further comprising:forwarding a re-invite for the intended communication in the eventverifying resource availability for the intended communication indicatesavailability of resources from the calling party network to the calledparty network.
 14. A method comprising: receiving at a first network anotice of an intended communication to a called party network, thenotice of intended communication including a first priority according toa first priority scheme, wherein the intended communication requires atleast one resource for supporting a streaming data protocol between acalling party network and the called party network; mapping the firstpriority to a corresponding second priority for a second priority schemeutilized in the first network; verifying resource availability of atleast one resource in the first network based on the correspondingsecond priority; and in parallel with said verifying, forwarding thenotice of an intended communication to a second network and toward thecalled party network prior to receiving an first indication of resourceavailability of the at least one resource in the first network requiredfor the intended communication.
 15. The method of claim 14 wherein themapping of the first priority to the corresponding second priority isbased on negotiation via a key exchange protocol between the firstnetwork and the calling party network.
 16. The method of claim 14wherein the mapping of the first priority to the corresponding secondpriority is based on predetermined correspondences.
 17. The method ofclaim 14 wherein the mapping of the first priority to the secondpriority is based on a default correspondence.
 18. The method of claim14 wherein the notice of intended communication includes a resourcepriority header.
 19. The method of claim 14 further comprising:receiving at the first network a second indication of resourceavailability of at least one resource at a third network required forthe intended communication.
 20. The method of claim 19 furthercomprising: forwarding a re-invite of the intended communication to thesecond network and toward the called party network in the event thefirst indication and the second indication indicate resourceavailability for at least one resource in each network from the callingparty network to the called party network.